When to pot up seedlings?

Just wondering when do i pot up seedlings into their own individual pots? Got seedlings of Trichocerus, Gymnocalycium, Melenocactus, Copiapoa, Astrophytum, Blossfeldia and Lithops. I know some are going to take alot longer to get to a size where i can pot them up but what stage do they need to be at?

I would say when they get over crowded - but initially they like to grow together in a mass. Don't forget to take into account the season you pot them up because you want them to move on quickly, so they heat light and time to mend their broken roots. If you pot them at the wrong season, they could go backwards or worse - die

ok so just leave all my seedlings untill spring? Alot are not close enough to ever get crowded so i was thinking once they get to the stage of looking like cacti rather than little green things

Yep - best to plant them when they look more like cacti than naked green lumps Cacti are social critters and like being close to their own kind

Yep them get overcrowded before potting up. Like Calycium said they like to grow in a mass. It could be 12 months depending on how quick they grow

With the lithops the same applies, experts reckon by overcrowding lithops the runts will die off and this way you only get strong healthy plants.

I have seen them stacked in both lithops and cacti, just be patient............if you can lol